Identifying a beam for accessing a target cell of a wireless hanover

ABSTRACT

In accordance with particular embodiments, there is disclosed herein a method performed by a wireless device for handover. The method comprises receiving a first handover message from a source network node associated with a source cell. The first handover message comprises an identification of a target cell and access information associated with the target cell. The target cell is different than the source cell and comprises one or more beams. The method also includes identifying at least one beam from among the one or more beams of the target cell. The at least one beam is identified based on the identification of the target cell and the access information from the first handover message. The method further includes accessing the target cell using the identified at least one beam.

TECHNICAL FIELD

Embodiments presented herein relate to wireless handover, and inparticular to methods, network nodes, wireless devices, computerprograms, or computer program products for wireless handover.

BACKGROUND

One of the design goals of the New Radio (NR) for 5G wirelesscommunication is to support operation on high frequencies (e.g., 28GHz), where massive beamforming is needed to maintain adequate radiocoverage. This has an impact on a number of system functions, includingmobility procedures such as handover (HO). The HO procedure used inlegacy long term evolution (LTE) (e.g., 4G wireless communication) isdepicted in FIG. 1.

In legacy wireless communication systems, the user equipment (UE) hasbeen configured with event based report triggering criteria. Once atriggering criterion has been met, the UE sends a measurement report tothe source eNB (the eNB to which the UE is currently connected) viaradio resource control (RRC). The measurement reporting parametersprovided by the network aim to minimize both ping-pong as well ashandover failures. For intra-frequency mobility this is typicallyachieved by configuring an A3 measurement event so that a report istriggered when a neighbour cell is found to be a few dB better than theserving cell. Due to measurement errors in bad radio conditions and dueto the necessary filtering, the actual difference in signal strength maybe worse than anticipated by the configured event threshold. Aconsequence of this is that many measurement reports and the subsequentmobility related RRC signalling are exchanged in challenging radioconditions and are hence error prone.

The mechanisms designed in LTE for mobility do not provide sufficientmechanisms for mobility in beam based systems. In particular, in abeam-based system like NR, and especially in higher frequency bands, theserving radio link to the UE may become impaired much more rapidly thanin conventional LTE deployments. As the UE is moving out of the currentserving beam coverage area, it may not be possible to conduct RRCsignalling via the serving node to complete the HO procedure.

SUMMARY

An object of embodiments herein is to provide mobility mechanisms, suchas handover, that support beam based systems. According to certainembodiments, a method performed by a wireless device for handoverincludes receiving a first handover message from a source network nodeassociated with a source cell. The first handover message includes anidentification of a target cell and access information associated withthe target cell. The target cell is different than the source cell andcomprises one or more beams. The access information includes beamrelated information. The method also includes identifying at least onebeam from among the one or more beams of the target cell based on theidentification of the target cell and the access information from thefirst handover message. The method additionally includes accessing thetarget cell using the identified at least one beam.

In some embodiments, the target cell is associated with a second networknode that is different than the source network node. In certainembodiments, the access information comprises Random Access Channel(RACH) information. In particular embodiments the target cell has atleast two beams. In such embodiments, the access information maycomprise an indication of allowed beams associated with the target cell.The allowed beams may be fewer than all of the beams of the target cell.In some embodiments, the access information may include a random accesspreamble that is mapped to each of the allowed beams of the target cell.In certain embodiments, the access information includes common randomaccess configuration information and dedicated random access resourcesfor the allowed beams. In certain embodiments, accessing the target cellusing the identified at least one beam may comprise accessing the targetcell using a contention based random access procedure. In particularembodiments, accessing the target cell using the identified at least onebeam may comprise accessing the target cell without first reading systeminformation associated with the target cell.

According to certain embodiments, a wireless device for handoverincludes a wireless interface configured to receive a first handovermessage from a source network node. The source network node isassociated with a source cell. The first handover message includes anidentification of a target cell and access information associated withthe target cell. The target cell is different than the source cell andcomprises one or more beams. The wireless device also includesprocessing circuitry configured to identify at least one beam from amongthe one or more beams of the target cell based on the identification ofthe target cell and the access information from the first handovermessage. The wireless device also includes an input and output interfacethat is configured to receive input information and provide outputinformation. The wireless device further includes a power source that isconfigured to provide power to the wireless interface, processingcircuitry and input and output interface. The wireless interface isfurther configured to access the target cell using the identified atleast one beam.

In accordance with certain embodiments, a wireless communication systemfor handover includes at least two network nodes. The wirelesscommunication system also includes at least one wireless devicewirelessly connected to a first of the at least two network nodes. Thefirst network node is configured to determine access informationassociated with a second of the at least two network nodes for the atleast one wireless device. The first network node is also configured toprepare the access information associated with the second network nodeto be transmitted to the at least one wireless device. The at least onewireless device is configured to receive a handover message from thefirst network node. The handover message comprising an identificationassociated with the second network node and the access informationassociated with the second network node. The at least one wirelessdevice is also configured to identify and select at least one beam fromthe second network node. The at least one wireless device is furtherconfigured to access the second network node using the identified andselected at least one beam based on the access information from thehandover message.

In accordance with certain embodiments, a wireless device for handovercomprises a processor and computer readable storage media. The storagemedia contains instructions that are executable by the processor. Whenthe instructions are executed, the wireless device is operative toreceive a first handover message from a source network node associatedwith a source cell. The first handover message comprises anidentification of a target cell and access information associated withthe target cell. The target cell is different than the source cell andcomprises one or more beams. The wireless device is also operative toidentify at least one beam from among the one or more beams of thetarget cell based on the identification of the target cell and theaccess information from the first handover message. The wireless deviceis additionally operative to access the target cell using the identifiedat least one beam.

In accordance with some embodiments, a wireless device for handovercomprises a receiver unit configured to receive a first handover messagefrom a source network node associated with a source cell. The firsthandover message comprises an identification of a target cell and accessinformation associated with the target cell. The target cell isdifferent than the source cell and comprises one or more beams. Thewireless device also comprises an identification unit configured toidentify at least one beam from among the one or more beams of thetarget cell based on the identification of the target cell and theaccess information from the first handover message. The wireless devicefurther includes an access unit configured to access the target cellusing the identified at least one beam.

Advantageously one or more embodiments provide additional information inthe contents of the handover command related to target beams inneighbouring cells. Additionally, one or more embodiments provide anextension of the synchronization and random access procedure to allowfor the selection of a beam in the target cell. Certain embodimentsfurther provide the ability to associate the handover command with acondition (e.g., RRCConnectionReconfiguration with mobilityControlInfo).As soon as the UE determines the condition to be fulfilled, it executesthe handover in accordance with the handover command.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated.

It is to be noted that any feature of any of the above embodiments maybe applied to any other embodiment, wherever appropriate. Likewise, anyadvantage of any of the embodiments herein may apply to the otherembodiments, and vice versa. Other objectives, features and advantagesof the enclosed embodiments will be apparent from the following detaileddisclosure, attached claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Particular embodiments are now described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 illustrates a signalling diagram for active mode mobility inlegacy LTE wireless communication systems;

FIG. 2 illustrates a block diagram of a wireless network in accordancewith particular embodiments;

FIG. 3 illustrates a block diagram of a user equipment in accordancewith particular embodiments;

FIG. 4 illustrates a signalling diagram of a handover in accordance withparticular embodiments;

FIG. 5 illustrates a signalling diagram of a conditional handoverexecution based on downlink received signal measurements, in accordancewith particular embodiments;

FIG. 6 illustrates a flowchart of a method for wireless handover, inaccordance with particular embodiments; and

FIG. 7 illustrates a block diagram of the functional units of a wirelessdevice and a network node, in accordance with particular embodiments.

DETAILED DESCRIPTION

Some of the embodiments contemplated by the claims will now be describedmore fully hereinafter with reference to the accompanying drawings.Other embodiments, however, are contained within the scope of the claimsand the claims should not be construed as limited to only theembodiments set forth herein; rather, these embodiments are provided byway of example so that this disclosure will assist in conveying theinventive concept to those skilled in the art. Like numbers refer tolike elements throughout the description.

Although the embodiments described herein may be implemented in anyappropriate type of system using any suitable components, particularembodiments described herein may be implemented in a wireless networksuch as the example wireless communication network illustrated in FIG.2. In the example embodiment illustrated in FIG. 2, the wirelesscommunication network provides communication and other types of servicesto one or more wireless devices. In the illustrated embodiment, thewireless communication network includes network nodes 220 and 220 a thatfacilitate wireless device 210's access to and/or use of the servicesprovided by and through the wireless communication network. The wirelesscommunication network may further include any additional elementssuitable to support communication between wireless devices or between awireless device and another communication device, such as a landlinetelephone.

Network 250 may comprise one or more backbone networks, IP networks,public switched telephone networks (PSTNs), packet data networks,optical networks, wide area networks (WANs), local area networks (LANs),wireless local area networks (WLANs), wired networks, wireless networks,metropolitan area networks, and other networks to enable communicationbetween devices.

The wireless communication network may represent any type ofcommunication, telecommunication, data, cellular, and/or radio networkor other type of system. In particular embodiments, the wirelesscommunication network may be configured to operate according to specificstandards or other types of predefined rules or procedures. Thus,particular embodiments of the wireless communication network mayimplement communication standards, such as Global System for MobileCommunications (GSM), Universal Mobile Telecommunications System (UMTS),Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, or 5Gstandards; wireless local area network (WLAN) standards, such as theIEEE 802.11 standards; and/or any other appropriate wirelesscommunication standard, such as the Worldwide Interoperability forMicrowave Access (WiMax), Bluetooth, and/or ZigBee standards.

FIG. 2 illustrates a wireless network comprising a more detailed view ofnetwork node 220 and wireless device (WD) 210, in accordance with aparticular embodiment. For simplicity, FIG. 2 only depicts network 250,network nodes 220 and 220 a, and WD 210. The detailed view of networknode 220 comprises the hardware components of interface 221, antenna 221a (may be referred to collectively as an interface or a wirelessinterface), processor 222, and storage 223. Similarly, the detailed viewof WD 210 comprises the hardware components of interface 211 and antenna211 a (may be referred to collectively as interface or wirelessinterface) processor 212, and storage 213. These components may worktogether in order to provide network node and/or wireless devicefunctionality, such as providing wireless connections in a wirelessnetwork and/or facilitating in the handover of wireless connections in abeam based network. In different embodiments, the wireless network maycomprise any number of wired or wireless networks, network nodes, basestations, controllers, wireless devices, relay stations, and/or anyother components that may facilitate or participate in the communicationof data and/or signals whether via wired or wireless connections.

A network node may refer to equipment capable, configured, arrangedand/or operable to communicate directly or indirectly with a wirelessdevice and/or with other equipment in the wireless communication networkthat enable and/or provide wireless access to the wireless device orwhich provide some service to a wireless device that has accessed thewireless communication network. Examples of network nodes include, butare not limited to, access points (APs), in particular radio accesspoints, and base stations (BSs), such as radio base stations. Particularexamples of radio base stations include Node Bs, and evolved Node Bs(eNBs). Base stations may be categorized based on the amount of coveragethey provide (or, stated differently, their transmit power level) andmay then also be referred to as femto base stations, pico base stations,micro base stations, or macro base stations. A network node may alsoinclude one or more (or all) parts of a distributed radio base stationsuch as centralized digital units and/or remote radio units (RRUs),sometimes referred to as Remote Radio Heads (RRHs). Such remote radiounits may or may not be integrated with an antenna as an antennaintegrated radio. Parts of a distributed radio base station may also bereferred to as nodes in a distributed antenna system (DAS). As aparticular non-limiting example, a base station may be a relay node or arelay donor node controlling a relay node.

Yet further examples of network nodes include multi-standard radio (MSR)radio equipment such as MSR BSs, network controllers such as radionetwork controllers (RNCs) or base station controllers (BSCs), basetransceiver stations (BTSs), transmission points, transmission nodes,Multi-cell/multicast Coordination Entities (MCEs), core network nodes(e.g., MSCs, MMEs), O&M nodes, OSS nodes, SON nodes, positioning nodes(e.g., E-SMLCs), and/or MDTs.

In FIG. 2, the components of network node 220 are depicted as singleboxes located within a single larger box. In practice however, a networknode may comprise multiple different physical components that make up asingle illustrated component (e.g., interface 221 may comprise terminalsfor coupling wires for a wired connection and a radio transceiver for awireless connection). As another example, network node 220 may be avirtual network node in which multiple different physically separatecomponents interact to provide the functionality of network node 220(e.g., processor 222 may comprise three separate processors located inthree separate enclosures, where each processor is responsible for adifferent function for a particular instance of network node 220).Similarly, network node 220 may be composed of multiple physicallyseparate components (e.g., a NodeB component and a RNC component, a BTScomponent and a BSC component, etc.), which may each have their ownrespective processor, storage, and interface components. In certainscenarios in which network node 220 comprises multiple separatecomponents (e.g., BTS and BSC components), one or more of the separatecomponents may be shared among several network nodes. For example, asingle RNC may control multiple NodeB's. In such a scenario, each uniqueNodeB and RNC pair may be considered a separate network node. In someembodiments, network node 220 may be configured to support multipleradio access technologies (RATs). In such embodiments, some componentsmay be duplicated (e.g., separate storage 223 for the different RATs)and some components may be reused (e.g., the same antenna 221 a may beshared by the RATs).

Processor 222 may be a combination of one or more of a microprocessor,controller, microcontroller, central processing unit, digital signalprocessor, application specific integrated circuit, field programmablegate array, or any other suitable computing device, resource, orcombination of hardware and software and/or encoded logic operable toprovide, either alone or in conjunction with other network node 220components, such as storage 223, network node 220 functionality. Forexample, processor 222 may execute instructions stored in storage 223.Such functionality may include providing various wireless featuresdiscussed herein to a wireless device, such as WD 210, including any ofthe features or benefits disclosed herein.

Storage 223 may comprise any form of non-transitory volatile ornon-volatile computer readable memory including, without limitation,persistent storage, solid state memory, remotely mounted memory,magnetic media, optical media, random access memory (RAM), read-onlymemory (ROM), removable media, or any other suitable local or remotememory component. Storage 223 may store any suitable instructions, dataor information, including software and/or encoded logic, utilized bynetwork node 220. Storage 223 may be used to store any calculations madeby processor 222 and/or any data received via interface 221.

Network node 220 also comprises interface 221 which may be used in thewired or wireless communication of signalling and/or data betweennetwork node 220, network 250, and/or WD 210. For example, interface 221may perform any formatting, coding, or translating that may be needed toallow network node 220 to send and receive data from network 250 over awired connection. Interface 221 may also include a radio transmitterand/or receiver that may be coupled to or a part of antenna 221 a. Theradio may receive digital data that is to be sent out to other networknodes or WDs via wireless connections. The radio may convert the digitaldata into a radio signal having the appropriate channel and bandwidthparameters. The radio signal may then be transmitted via antenna 221 ato the appropriate recipient (e.g., WD 210). The radio signal maycomprise one or more beams.

Antenna 221 a may be any type of antenna capable of transmitting andreceiving data and/or signals wirelessly. In some embodiments, antenna221 a may comprise one or more omni-directional, sector or panelantennas operable to transmit/receive radio signals between, forexample, 1 GHz and 100 GHz. An omni-directional antenna may be used totransmit/receive radio signals in any direction, a sector antenna may beused to transmit/receive radio signals from devices within a particulararea, and a panel antenna may be a line of sight antenna used totransmit/receive radio signals in a relatively straight line.

A wireless device (WD) may refer to a device capable, configured,arranged and/or operable to communicate wirelessly with network nodesand/or other wireless devices. Communicating wirelessly may involvetransmitting and/or receiving wireless signals using electromagneticsignals, radio waves, infrared signals, and/or other types of signalssuitable for conveying information through air. In particularembodiments, a wireless device may be configured to transmit and/orreceive information without direct human interaction. For instance, awireless device may be designed to transmit information to a network ona predetermined schedule, when triggered by an internal or externalevent, or in response to requests from the network. Examples of wirelessdevices include, but are not limited to, user equipment (UE) such assmart phones. Further examples include wireless cameras,wireless-enabled tablet computers, laptop-embedded equipment (LEE),laptop-mounted equipment (LME), USB dongles, and/or wirelesscustomer-premises equipment (CPE). In some embodiments, a wirelessdevice may support device-to-device (D2D) communication, for example byimplementing a 3GPP standard for sidelink communication, and may in thiscase be referred to as a D2D communication device.

As one specific example, a wireless device may represent a UE configuredfor communication in accordance with one or more communication standardspromulgated by the 3rd Generation Partnership Project (3GPP), such as3GPP's GSM, UMTS, LTE, and/or 5G standards. A UE may not necessarilyhave a “user” in the sense of a human user who owns and/or operates therelevant device. Instead, a UE may represent a device that is intendedfor sale to, or operation by, a human user but that may not initially beassociated with a specific human user, such as smart sensors or smartmeters. The features, functionality, steps, and benefits described withrespect to a WD may be equally applicable to a UE and vice versa.

As yet another specific example, in an Internet of Things (IoT)scenario, a wireless device may represent a machine or other device thatperforms monitoring and/or measurements, and transmits the results ofsuch monitoring and/or measurements to another wireless device and/or anetwork node. The wireless device may in this case be amachine-to-machine (M2M) device, which may in a 3GPP context be referredto as a machine-type communication (MTC) device. As one particularexample, the wireless device may be a UE implementing the 3GPP narrowband internet of things (NB-IoT) standard. Particular examples of suchmachines or devices are sensors, metering devices such as power meters,industrial machinery, or home or personal appliances, e.g.refrigerators, televisions, personal wearables such as watches etc. Inother scenarios, a wireless device may represent a vehicle or otherequipment that is capable of monitoring and/or reporting on itsoperational status or other functions associated with its operation.

A wireless device as described above may represent the endpoint of awireless connection, in which case the device may be referred to as awireless terminal. Furthermore, a wireless device as described above maybe mobile, in which case it may also be referred to as a mobile deviceor a mobile terminal.

As depicted in FIG. 2, WD 210 may be any type of wireless devicedescribed above including a wireless endpoint, mobile station, mobilephone, wireless local loop phone, smartphone, user equipment, desktopcomputer, PDA, cell phone, tablet, laptop, VoIP phone or handset, whichis able to wirelessly send and receive data and/or signals to and from anetwork node, such as network nodes 220 or 220 a and/or other WDs. Likenetwork node 220, the components of WD 210 are depicted as single boxeslocated within a single larger box, however in practice a wirelessdevice may comprises multiple different physical components that make upa single illustrated component (e.g., storage 213 may comprise multiplediscrete microchips, each microchip representing a portion of the totalstorage capacity). Additionally, in some embodiments, some componentsmay be remote from WD 210 (e.g., storage 213 may comprise some localstorage and some cloud based storage capacity).

Processor 212 may be a combination of one or more of a microprocessor,controller, microcontroller, central processing unit, digital signalprocessor, application specific integrated circuit, field programmablegate array, or any other suitable computing device, resource, orcombination of hardware and, software and/or encoded logic operable toprovide, either alone or in combination with other WD 210 components,such as storage 213, WD 210 functionality. Such functionality mayinclude providing various wireless features discussed herein, includingany of the features or benefits disclosed herein.

Storage 213 may be any form of volatile or non-volatile memoryincluding, without limitation, persistent storage, solid state memory,remotely mounted memory, magnetic media, optical media, random accessmemory (RAM), read-only memory (ROM), removable media, or any othersuitable local or remote memory component. Storage 213 may store anysuitable data, instructions, or information, including software andencoded logic, utilized by WD 210. Storage 213 may be used to store anycalculations made by processor 212 and/or any data received viainterface 211.

Interface 211 may be used in the wireless communication of signallingand/or data between WD 210 and network node 220. For example, interface211 may perform any formatting, coding, or translating that may beneeded to allow WD 210 to send and receive data from network node 220over a wireless connection. Interface 211 may also include a radiotransmitter and/or receiver that may be coupled to or a part of antenna211 a. The radio may receive digital data that is to be sent out tonetwork node 220 via a wireless connection. The radio may convert thedigital data into a radio signal having the appropriate channel andbandwidth parameters. The radio signal may then be transmitted viaantenna 211 a to network node 220.

Antenna 211 a may be any type of antenna capable of transmitting andreceiving data and/or signals wirelessly. In some embodiments, antenna211 a may comprise one or more omni-directional, sector or panelantennas operable to transmit/receive radio signals between 1 GHz and100 GHz. For simplicity, antenna 211 a may be considered a part ofinterface 211 to the extent that a wireless signal is being used.

FIG. 3 illustrate a block diagram of a UE. As shown in FIG. 3, UE 300 isan example wireless device. UE 300 includes an antenna 305, radiofront-end circuitry 310, processing circuitry 315, input interface 320,output interface 325, a computer-readable storage 330, and power source335. Antenna 305 may include one or more antennas or antenna arrays, andis configured to send and/or receive wireless signals, and is connectedto radio front-end circuitry 310. In certain alternative embodiments, UE300 may not include antenna 305, and antenna 305 may instead be separatefrom UE 300 and be connectable to UE 300 through an interface or port.

The radio front-end circuitry 310 may comprise various filters andamplifiers, is connected to antenna 305 and processing circuitry 315,and is configured to condition signals communicated between antenna 305and processing circuitry 315. In certain alternative embodiments, UE 300may not include radio front-end circuitry 310, and processing circuitry315 may instead be connected to antenna 305 without radio front-endcircuitry 310.

Processing circuitry 315 may include one or more of radio frequency (RF)transceiver circuitry, baseband processing circuitry, and applicationprocessing circuitry. In some embodiments, the RF transceiver circuitry,baseband processing circuitry, and application processing circuitry maybe on separate chips or sets of chips. In alternative embodiments, partor all of the baseband processing circuitry and application processingcircuitry may be combined into one chip or set of chips, and the RFtransceiver circuitry may be on a separate chips or sets of chips. Instill alternative embodiments, part or all of the RF transceivercircuitry and baseband processing circuitry may be on the same chip orset of chips, and the application processing circuitry may be on aseparate chip or set of chips. In yet other alternative embodiments,part or all of the RF transceiver circuitry, baseband processingcircuitry, and application processing circuitry may be combined in thesame chip or set of chips. Processing circuitry 315 may include, forexample, one or more central processing units (CPUs), one or moremicroprocessors, one or more application specific integrated circuits(ASICs), and/or one or more field programmable gate arrays (FPGAs).

In particular embodiments, some or all of the functionality describedherein as being provided by a wireless device or UE may be provided byprocessing circuitry 315 executing instructions stored on acomputer-readable storage medium 330. In alternative embodiments, someor all of the functionality may be provided by processing circuitry 315without executing instructions stored on a computer-readable medium,such as in a hard-wired manner. In any of those particular embodiments,whether executing instructions stored on a computer-readable storagemedium or not, the processing circuitry can be said to be configured toperform the described functionality. The benefits provided by suchfunctionality are not limited to the processing circuitry 315 alone orto other components of UE 300, but are enjoyed by the wireless device asa whole, and/or by end users and the wireless network generally.

Antenna 305, radio front-end circuitry 310, and/or processing circuitry315 may be configured to perform any receiving operations describedherein as being performed by a wireless device. Any information, dataand/or signals may be received from a network node and/or anotherwireless device.

The processing circuitry 315 may be configured to perform anydetermining operations described herein as being performed by a wirelessdevice or UE. Determining as performed by processing circuitry 315 mayinclude processing information obtained by the processing circuitry 315by, for example, converting the obtained information into otherinformation, comparing the obtained information or converted informationto information stored in the wireless device, and/or performing one ormore operations based on the obtained information or convertedinformation, and as a result of said processing making a determination.

Antenna 305, radio front-end circuitry 310, and/or processing circuitry315 may be configured to perform any transmitting or receivingoperations described herein as being performed by a wireless device. Anyinformation, data and/or signals may be transmitted or received to anetwork node and/or another wireless device or UE. These components maybe referred to collectively as an interface when used it thetransmitting or receiving of data and/or signals

Computer-readable storage medium 330 is generally operable to storeinstructions, such as a computer program, software, an applicationincluding one or more of logic, rules, code, tables, etc. and/or otherinstructions capable of being executed by a processor. Examples ofcomputer-readable storage medium 330 include computer memory (forexample, Random Access Memory (RAM) or Read Only Memory (ROM)), massstorage media (for example, a hard disk), removable storage media (forexample, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or anyother volatile or non-volatile, non-transitory computer-readable and/orcomputer-executable memory devices that store information, data, and/orinstructions that may be used by processing circuitry 315. In someembodiments, processing circuitry 315 and computer-readable storagemedium 330 may be considered to be integrated.

Shown in FIG. 3, but not in FIG. 2, are input interface 320 and outputinterface 325. These may be configured to receive input information andprovide output information. For example, a user associated with WD 210may use input interface 320 to select audio or video content to bestreamed to WD 210 for playback on output interface 325. The streamedcontent may be streamed to WD 210 as WD 210 moves between geographicareas associated with the source cell to the target cell.

As illustrated, UE 300 includes input interface 320. Input interface320, may comprise any devices and circuits configured to allow input ofinformation into UE 300, and are connected to processing circuitry 315to allow processing circuitry 315 to process the input information. Forexample, input interface 320 may include a microphone, a proximity orother sensor, keys/buttons, a touch display, one or more cameras, a USBport, or other input elements.

Output interface 325 may comprise any devices and circuits configured toallow output of information from UE 300, and are connected to processingcircuitry 315 to allow processing circuitry 315 to output informationfrom UE 300. For example, output interface 315 may include a speaker, adisplay, vibrating circuitry, a USB port, a headphone interface, orother output elements. Using one or more input interface 320 and outputinterface 325, UE 300 may communicate with end users and/or the wirelessnetwork, and allow them to benefit from the functionality describedherein.

Shown in FIG. 3, but not in FIG. 2, WD 210 may also comprise powersource 335. Power source 335 may be configured to provide power to thevarious components of WD 210, such as wireless interface 211, processingcircuitry 212, storage 213, input interface 320, output interface 325and any other components of WD 210 that rely on electrical power tooperate.

As illustrated, UE 300 includes power source 335. Power source 335 maycomprise power management circuitry. Power source 335 may receive powerfrom a power supply, which may either be comprised in, or be externalto, power source 335. For example, UE 300 may comprise a power supply inthe form of a battery or battery pack which is connected to, orintegrated in, power source 335. Other types of power sources, such asphotovoltaic devices, may also be used. As a further example, UE 300 maybe connectable to an external power supply (such as an electricityoutlet) via an input circuitry or interface such as an electrical cable,whereby the external power supply supplies power to power source 335.Power source 335 may be connected to radio front-end circuitry 310,processing circuitry 315, and/or computer-readable storage medium 330and be configured to supply UE 300, including processing circuitry 315,with power for performing the functionality described herein.

UE 300 may also include multiple sets of processing circuitry 315,computer-readable storage medium 330, radio circuitry 310, and/orantenna 305 for different wireless technologies integrated into wirelessdevice 300, such as, for example, GSM, WCDMA, LTE, NR, Wi-Fi, orBluetooth wireless technologies. These wireless technologies may beintegrated into the same or different chips or sets of chips s and othercomponents within wireless device 300.

Alternative embodiments of UE 300 may include additional componentsbeyond those shown in FIG. 3 that may be responsible for providingcertain aspects of the UE's functionality, including any of thefunctionality described herein and/or any functionality necessary tosupport the solution described herein.

The following description may help illustrate how the components ofFIGS. 2 and 3 may work to provide the features and benefits of wirelesshandover of certain embodiments disclosed herein. For simplicity, thedescription below will focus on the components of FIG. 2, but is equallyapplicable with the corresponding components of FIG. 3. In the scenariodescribed below, network node 220 may be referred to as a source networknode because it is WD 210's current source for wireless access. Sourcenetwork node 220 may be associated with one or more cells. Each cell isassociated with, and provides wireless coverage for, a particulargeographic area. The cell currently being used by WD 210 may be referredto as a source cell while the cell to which WD 210 is to be handed overmay be referred to as a target cell. While it may be that both thesource cell and the target cell are provided by the same network node,for purposes of simplicity herein it may be assumed that the source cellis associated with network node 220 and the target cell is associatedwith network node 220 a. It may also be assumed that target network node220 a uses a plurality of beams in providing wireless coverage withinthe target cell.

Interface 211 may comprise a wireless interface suitable for sending andreceiving data, messages, signaling and/or other information(collectively “data”) over an air interface. In certain embodiments,wireless interface 211 may be configured to receive a first handovermessage from network node 220. In certain embodiments, the firsthandover message may include multiple pieces of information that can beused by WD 210 in the handover from the source cell to the target cell.For example, the handover message may include an identification of thetarget cell and access information associated with the target cell, suchas information related to the beams provided by target network node 220a for the target cell. The beams provided may include all the beamsassociated with the target cell, or a subset thereof. The subset may bea predetermined subset (e.g., certain beams reserved for handover) orselected based on one or more conditions (e.g., current load of thebeams associated with the target cell). In some embodiments, the accessinformation may be Random Access Channel (RACH) information associatedwith the target cell. In some embodiments, the access information mayinclude a random access preamble mapped to each of the allowed beams ofthe target cell. In some embodiments, the access information may includecommon random access configuration information and dedicated randomaccess resources for the allowed beams. The allowed beams may be thosebeams which WD 210 will be allowed to use to access the target cell. Theallowed beams may be a subset of the beams associated with the targetcell or the available beams associated with the target cell.

The handover message may be determined and transmitted by source networknode 220. More specifically, interface 221 of source network node 220may receive certain information from target network node 220 a (e.g.,available beams, allowed beams, configuration/synchronizationinformation for the beams, etc.). Processing circuitry 222 may then usethe information along with information from WD 210 to determine theaccess information that is to be included in the handover messageprovided to WD 210.

Processing circuitry 212 of wireless device 210 may be used to identifyat least one beam from among the one or more beams of the target cell.If only one beam is provided, then that may be the identified beam, ifmore than one beam is provide, processor 212 may determine the beam bestsuited for WD 210. The beam(s) may be identified based on theidentification of the target cell and the access information from thefirst handover message. In some embodiments and/or scenarios, thebeam(s) may be identified based on measurements made of the beamsprovided by the target network node. The measurements may be made onany/all beams received by interface 211 or on certain specified beams.The beams may be specified in any of a variety of different ways such asin a message provided to WD 210, preconfigured and stored in storage213, or otherwise provided to WD 210. In some embodiments the specifiedbeams may be fewer than all of the beams of the target cell or fewerthan all of the beams detectable by WD 210. In some embodiments, WD 210may measure one or more characteristics of the beams of the target celland then send a report to source network node 220 via interface 211. Theinformation from the report may be used in identifying the beams.

Once processing circuitry 212 has selected the appropriate beam, and anyother handover pre-requisites have been satisfied, wireless interface211 may be configured to access the target cell using the identified atleast one beam. In some embodiments wireless interface 211 may accessthe target cell using a contention based random access procedure. Thisaccess may be based on information received in the handover message. Insome embodiments, wireless interface 211 may access the target cellwithout having to first read system information associated with thetarget cell (e.g., random access parameters or RACH). That is, sourcenode 220 may include sufficient details in the access information toallow WD 210 to access the target cell without needing that informationfrom target node 220 a.

The components described above with respect to FIGS. 2 and 3 may be usedto modify the legacy mobility procedure (illustrated in FIG. 1). FIG. 4illustrates a signalling diagram of the handover procedure in accordancewith particular embodiments. The order of the signals is similar to thelegacy procedure however the information and how it is determined andused is different. Depending on the embodiment, these differences can bediscussed based on the information contained in handover command 430 andthe corresponding synchronization and random access procedure 440. Thedevices illustrated in FIG. 4 may, in some embodiments, comprise similarcomponents and provide similar functionality as described above whereinUE 410 may correspond to WD 210, serving gNB 420 may correspond tonetwork node 220 and target gNB 420 a may correspond to network node 220a.

In some embodiments, with respect to providing UE 410 with an identityof target gNB 420 a, HO command 430 may include only the cell identityassociated with target gNB 420 a. The cell identity can be signalledeither explicitly or implicitly via, for example, mobility referencesignal (MRS) configuration. HO command 430 may compriseRRCConnectionReconfiguration and mobilityControlInfo. Once the cellidentity is received by an interface of UE 410 and processed, aprocessor therein may select any beam with the correct cell identitydetected by the interface of UE 410. UE 410 then reads the random accessparameters from system information and uses those for the initialsynchronization and random access 440 on the selected beam. In someembodiments, the random access may be a contention based random accessprocedure. These embodiments have the benefit of requiring a relativelysmall amount of signalling and network configuration in HO command 430but may result in a handover failure if there are other users competingfor the random access at the same time.

In some embodiments, in addition to the cell identity of target gNB 420a, HO command 430 may further include physical random access channel(PRACH) configuration information for the target cell. This informationmay be explicitly signalled in HO command 430, or it may be derived fromother parameters, such as via configuration of mobility referencesignals. Depending on the scenario and/or embodiment, multiple PRACHconfigurations may be provided to enable different random access (RA)parameters for different beams or beam groups. An interface of UE 410may receive HO command 430 and a processor of UE 410 may thenautonomously select a beam associated with the correct cell identity. UE410 then uses the provided PRACH parameters from HO command 430 for theinitial synchronization and random access 440 on the selected beam. Thishas the benefit of allowing the network to provide a dedicated handoverconfiguration for UE 410, but requires some additional configuration andsignalling as part of HO command 430.

In some embodiments, in addition to the cell identity and PRACHconfiguration information of target gNB 420 a, HO command 430 mayfurther include a list of allowed beams from target gNB 420 a. The listof allowed beams may comprise a list of beam IDs. The list of beam IDsmay be fewer than all the beams associated with target gNB 420 a. Thistarget cell information (including the list of beams) may be explicitlysignalled, or may be derived from other parameters, such asconfiguration of mobility reference signals. Depending on the scenarioand/or embodiment multiple PRACH configurations may be provided toenable different RA parameters for different beams or beam groups. HOcommand 430 is received by an interface of UE 410 and then a processorof UE 410 may autonomously select a beam from the list of allowed beamsassociated with the correct cell identity. UE 410 may then use therandom access parameters from HO command 430 and uses those for theinitial synchronization and random access 440 on the selected beam. Thishas the benefit of allowing the network to provide a dedicated handoverconfiguration for UE 410, and limiting the number of possible beams UE410 may select from, but requires again additional configuration andsignalling. Additionally, in some scenarios, UE 410 may end up in anon-optimal beam if the optimal beam is not on the list of allowed beamsprovided in HO command 430.

In some embodiments, in addition to the cell identity and PRACHconfiguration information of target gNB 420 a, HO command 430 mayinclude an indication of a single allowed beam. This target cellinformation may be explicitly signalled, or may be derived from otherparameters, such as configuration of mobility reference signals. Aninterface of UE 410 may receive HO command 430. Because there is onlythe one allowed beam, a processor of UE 410 does not need to make aselection of a beam, rather the processor of UE 410 synchronizes to theprovided beam with the correct cell identity based on the beam IDprovided in HO command 430. UE 410 then uses the random accessparameters from HO command 430 for the initial synchronization andrandom access 440. This has the benefit of allowing the network toprovide a dedicated handover configuration for UE 410 and explicitlyassigning the user to a particular beam, but it requires additionalconfiguration and signalling and may be more likely to result in the UEending up in a non-optimal beam.

In some embodiments, in addition to the cell identity, PRACHconfiguration information, and list of allowed beams, HO command 430 mayalso comprise a mapping between the allowed beams and a RA preamble (orsome other part of access configuration). This information may beexplicitly signalled, or may be derived from other parameters, such asconfiguration of MRS. An interface of UE 410 may receive HO command 430and then a processor of UE 410 may autonomously select a beam with thecorrect cell identity from the list of allowed beam IDs and set therandom access preamble value to the value corresponding to the selectedbeam identifier. UE 410 may then use the PRACH configuration informationand RA preamble corresponding to the selected beam in the initialsynchronization and random access 440. This has the benefit of allowingthe network to provide a dedicated handover configuration for UE 410,limiting the number of possible beams UE 410 may select from, andallowing the network to immediately detect which beam the UE hasselected, but requires again additional configuration and signalling andmay result in UE 410 using a non-optimal beam.

FIG. 5 illustrates a signalling diagram of a conditional handoverexecution based on downlink received signal measurements, in accordancewith particular embodiments. In some scenarios involving legacy systems,the probability of hand over failure could increase due to thedependency on the RRC signalling transmissions from the source cell at atime when the UE has already moved into the coverage area of the targetcell. To avoid the undesired dependence on the serving radio link at thetime (and radio conditions) where the UE should execute the handover,certain embodiments may provide the RRC signalling 530 to UE 510earlier. For example, the RRC signalling 530 may be sent prior to theoccurrence of a triggering event which would trigger sending RRCsignalling in legacy systems. This may be done, for example, byassociating the handover with a condition; when the condition isfulfilled, UE 510 may execute the handover in accordance with theinformation provided in HO command 530.

One such condition which might trigger handover could be that thereference signal of the target cell or beam becomes “x” dB stronger thanthe reference signal of the serving cell or beam. The threshold used ina preceding measurement reporting event could then be chosen lower thanthe one in the handover execution condition. This may allow the servingcell to prepare the handover upon reception of an early measurementreport and to provide the RRCConnectionReconfiguration withmobilityControlInfo at a time when the radio link between the sourcenetwork node and the UE is still stable. The execution of the handoveris done at a later point in time (and threshold) that is consideredoptimal for the handover execution.

Although FIG. 5 depicts an example with just serving node 520 and asingle target node 520 a. In practice there may often be many cells orbeams from many nodes that UE 510 may have reported as possiblecandidates based on its preceding RRM measurements. The RAN may thenhave the freedom to issue conditional handover instructions for severalcandidate network nodes. The RRCConnectionReconfiguration for each ofthose candidates may differ. For example, in terms of the HO executioncondition (RS to measure and threshold to exceed) as well as in terms ofthe RA preamble (denoted Uplink Signature Signal) to be sent when acondition is met. It may for example increase the HO success rate if theUE indicates by means of different RA preambles, which of the candidatetarget beams it selected (e.g., which beam fulfilled the HO executioncondition).

In some embodiments, the RRCConnectionReconfiguration for the early HOcommand could for example, also comprise a configuration for sending ULreference signals (similar to RA preambles) that both the serving aswell as the neighbour nodes attempt to receive. The network coulddetermine the most suitable cell based on the observed uplink signalsand issue a downlink reference signal upon which the UE executes thepre-conditioned HO command. A UE aiming to support URLLC with extremelyshort HO interruption could be configured to maintain the data exchangewith the source node while establishing the data exchange with thetarget node. As noted in a prior study, this may require additionalhardware elements in the UE and may therefore not be supported by allUEs.

FIG. 6 illustrates a flowchart of a method for wireless handover, inaccordance with particular embodiments. The method begins at step 600.Each step will include an indication of the device performing the stepin the embodiment illustrated in FIG. 6. The indicated device isprovided for ease of explanation, it is not necessarily required thatthe specified device perform the indicated step. In other embodiments,different devices may be used to perform one or more of the steps. Thedevices mentioned in FIG. 6 include a wireless device, a source networknode and a target network node. The source network node is the networknode providing wireless service to the wireless device at the start ofthe method. This service is provided in a source cell. The targetnetwork node is the network node to which the wireless device is to behanded over. The target network node provides wireless service in atarget cell. In some scenarios, the source cell and the target cell maybe provided by the same physical network node (e.g., a MSR networknode).

At step 605 the source network node determines the relevant accessinformation for the target cell. The target cell is different than thesource cell and includes one or more beams. The access information maybe determined based on information provided by the target network node.In some embodiments, the access information may be specific to aparticular UE or it may be generic such that it is applicable to any UE(or it may be general information that can be used create UE specificaccess information). In particular embodiments, the access informationmay comprise an indication of allowed beams. In some embodiments, theaccess information includes a random access preamble mapped to each ofthe allowed beams of the target cell. In certain embodiments, the accessinformation includes common random access configuration information anddedicated random access resources for the allowed beams.

At step 610 the source network node transmits a handover message thatincludes information that can be used by the wireless device to accessthe target cell. For example, the handover message may include anidentification of the target cell. As another example, the handovermessage may also include access information comprising beam relatedinformation associated with the target cell. In some embodiments, theaccess information may comprise Random Access Channel (RACH)information. In some embodiments, the beam related information mayrelate to fewer than all of the available beams of the target cell.

At step 615 the wireless device receives the handover message from thesource network node. In some embodiments, the handover message mayreceived in response to a triggering event (e.g., source signal qualityfalls below threshold, target signal quality exceeds threshold, etc.).This timing may be similar to legacy timing in terms of when thehandover message is sent. In some embodiments, the handover message mayreceived prior to the triggering event occurring. This may allow thesource network node to provide the wireless device with the accessinformation for the target cell at a time when the signal qualitybetween the source network node and the wireless device is better (ascompared to waiting for the triggering event to occur).

At step 620 the wireless device identifies at least one beam from thetarget cell based on the information in the handover message (e.g., theidentification of the target cell and the access information associatedwith the target cell). In some embodiments, the wireless device mayidentify a beam based on one or more quality characteristics of theavailable/allowed beams associated with the target cell. In somescenarios, only one beam may have been provided, in which the wirelessdevice simply selects the provided beam.

At step 625 the wireless device accesses the target cell using theidentified at least one beam. The target cell may be accessed based onthe access information received in the handover message received at step615. The target cell may be accessed without the wireless device havingto first read system information associated with the target cell. Insome embodiments, accessing the target cell using the identified atleast one beam may comprise accessing the target cell using a contentionbased random access procedure.

The steps described above are merely illustrative of certainembodiments. It is not required that all embodiments incorporate all thesteps above nor that the steps be performed in the exact order depictedin FIG. 6. Furthermore, some embodiments may include steps notillustrated in FIG. 6. For example, in some embodiments, the wirelessdevice may provide the source network node with an indication of asignal quality associated with one or more beams from the target node.

FIG. 7 illustrates a block diagram of the functional units of a wirelessdevice and a network node in accordance with particular embodiments. Inparticular, there is depicted the functional units of a particularwireless device 710 and network node 720. Other embodiments may includemore, fewer, or different functional units. Moreover, a single depictedunit may represent multiple similar units. For example, determine unit722 may represent multiple determine units configured to make differentdeterminations. The units may comprise software, computer programs,sub-routines, libraries, source code, or any other form of executableinstructions that are run by, for example, a processor. In this FIG. 7,wireless device 710 comprises receiver unit 712, identification unit714, and access unit 716; and network node 720 comprises determine unit722, prepare unit 724, transmit unit 726, and receive unit 728.

Starting with the components of WD 710, receiver unit 712 is configuredto receive a first handover message from a source network nodeassociated with a source cell. The first handover message comprises anidentification of a target cell and access information associated withthe target cell. In some embodiments there may be more than 2 potentialtarget cells. The target cell is different than the source cell andcomprises one or more beams. In some embodiments, the target cell isassociated with a second network node that is different than the sourcenetwork node. In some embodiments, the access information comprisesRandom Access Channel (RACH) information. In certain embodiments, thetarget cell has at least two beams and the access information comprisesan indication of allowed beams associated with the target cell. In suchembodiments, the allowed beams may be fewer than all of the beams of thetarget cell. In particular embodiments, the access information includesa random access preamble mapped to each of the allowed beams of thetarget cell. In some embodiments, the access information includes commonrandom access configuration information and dedicated random accessresources for the allowed beams.

Identification unit 714 is configured to identify at least one beam fromamong the one or more beams of the target cell based on theidentification of the target cell and the access information from thefirst handover message.

Access unit 716 is configured to access the target cell using theidentified at least one beam. In some embodiments, access unit 716 isfurther configured to access the target cell using a contention basedrandom access procedure. In certain embodiments, access unit 716 isfurther configured to access the target cell without first readingsystem information associated with the target cell.

Now looking at network node 720, determine unit 722 is configured todetermine access information associated with a second network node forthe at least one wireless device. The access information may bedetermined from information received from the target cell. In someembodiments, the information from the target cell may be combined withinformation stored by network node 720 to determine the accessinformation associated with the second network node.

Prepare unit 724 is configured to prepare the access informationassociated with the second network node to be transmitted to a wirelessdevice, such as wireless device 710.

Transmit unit 726 is configured to transmit the access information tothe wireless device.

Receive unit 728 is configured to receive access information from theother network node. The received access information is to be sent to thewireless device with or without modification to the access informationmade by network node 720 (e.g., network node may simply forward accessinformation provided by the target cell or it may modify the informationprovided by the target cell).

Any appropriate steps, methods, or functions may be performed through acomputer program product that may, for example, be executed by thecomponents and equipment illustrated in one or more of the figuresabove. For example, storage 223 may comprise computer readable means onwhich a computer program can be stored. The computer program may includeinstructions which cause processor 222 (and any operatively coupledentities and devices, such as interface 221 and storage 223) to executemethods according to embodiments described herein. The computer programand/or computer program product may thus provide means for performingany steps herein disclosed.

Certain aspects of the inventive concept have mainly been describedabove with reference to a few embodiments. However, as is readilyappreciated by a person skilled in the art, embodiments other than theones disclosed above are equally possible and within the scope of theinventive concept. Similarly, while a number of different combinationshave been discussed, all possible combinations have not been disclosed.One skilled in the art would appreciate that other combinations existand are within the scope of the inventive concept. Moreover, as isunderstood by the skilled person, the herein disclosed embodiments areas such applicable also to other standards and communication systems andany feature from a particular figure disclosed in connection with otherfeatures may be applicable to any other figure and or combined withdifferent features.

1. A method performed by a wireless device for handover, the methodcomprising: receiving a first handover message from a source networknode associated with a source cell, the first handover messagecomprising an identification of a target cell and access informationassociated with the target cell, wherein the target cell is differentthan the source cell and comprises one or more beams and the accessinformation comprises beam related information; identifying at least onebeam from among the one or more beams of the target cell based on theidentification of the target cell and the access information from thefirst handover message; and accessing the target cell using theidentified at least one beam.
 2. The method of claim 1, wherein thetarget cell is associated with a second network node, the second networknode being different than the source network node.
 3. The method ofclaim 1, wherein the access information comprises Random Access Channel(RACH) information.
 4. The method of claim 1, wherein the target cellhas at least two beams and the access information comprises anindication of allowed beams associated with the target cell, the allowedbeams comprising fewer than all of the beams of the target cell.
 5. Themethod of claim 4, wherein the access information includes a randomaccess preamble mapped to each of the allowed beams of the target cell.6. The method of claim 4, wherein the access information includes commonrandom access configuration information and dedicated random accessresources for the allowed beams.
 7. The method of claim 1, whereinaccessing the target cell using the identified at least one beamcomprises accessing the target cell using a contention based randomaccess procedure.
 8. The method of claim 1, wherein accessing the targetcell using the identified at least one beam comprises accessing thetarget cell without first reading system information associated with thetarget cell.
 9. A wireless device for handover comprising: a wirelessinterface configured to receive a first handover message from a sourcenetwork node associated with a source cell, the first handover messagecomprising an identification of a target cell and access informationassociated with the target cell, wherein the target cell is differentthan the source cell and comprises one or more beams; processingcircuitry configured to identify at least one beam from among the one ormore beams of the target cell based on the identification of the targetcell and the access information from the first handover message; and aninput and output interface configured to receive input information andprovide output information; a power source configured to provide powerto the wireless interface, processing circuitry and input and outputinterface; and wherein the wireless interface is further configured toaccess the target cell using the identified at least one beam.
 10. Thewireless device of claim 9, wherein the target cell is associated with asecond network node, the second network node being different than thesource network node.
 11. The wireless device of claim 9, wherein theaccess information comprises Random Access Channel (RACH) information.12. The wireless device of claim 9, wherein the target cell has at leasttwo beams and the access information comprises an indication of allowedbeams associated with the target cell, the allowed beams comprisingfewer than all of the beams of the target cell.
 13. The wireless deviceof claim 12, wherein the access information includes a random accesspreamble mapped to each of the allowed beams of the target cell.
 14. Thewireless device of claim 12, wherein the access information includescommon random access configuration information and dedicated randomaccess resources for the allowed beams.
 15. The wireless device of claim9, wherein the wireless interface configured to access the target cellusing the identified at least one beam is configured to access thetarget cell using a contention based random access procedure.
 16. Thewireless device of claim 9, wherein the wireless interface configured toaccess the target cell using the identified at least one beam isconfigured to access the target cell without first reading systeminformation associated with the target cell.
 17. A wirelesscommunication system for handover, the system comprising: at least twonetwork nodes; at least one wireless device wirelessly connected to afirst of the at least two network nodes; wherein the first network nodeis configured to: determine access information associated with a secondof the at least two network nodes for the at least one wireless device;and prepare the access information associated with the second networknode to be transmitted to the at least one wireless device; and whereinthe at least one wireless device is configured to: receive a handovermessage from the first network node, the handover message comprising anidentification associated with the second network node and the accessinformation associated with the second network node; identify and selectat least one beam from the second network node; and access the secondnetwork node using the identified and selected at least one beam basedon the access information from the handover message. 18-33. (canceled)